1. Field of the Invention
This invention relates to telephone answering devices of the type utilized to reproduce a recorded announcement in response to an incoming call and for recording incoming messages after the announcement has ended.
2. Brief Description of the Prior Art
A number of different types of telephone answering devices are known in the prior art-- all providing some form of machine-based telephone answering service for a telephone subscriber. Typically, modern telephone answering devices include a pair of record/playback tape systems or decks, one being used for recording a telephone subscriber's announcement and reproducing it to a calling party, the other for recording callers' messages for playback at the subscriber's convenience. In more basic forms of such equipment, the announcement tape deck is provided with a mandatory, fixed-length announcement cycle which must be completed before the apparatus is switched over to record incoming messages. Such a system is both inefficient and inconvenient in that the subscriber must tailor his announcement to fit the fixed announcement cycle provided, which is typically much longer than the duration of the usual announcement.
More advanced forms of telephone answering equipment provide an announcement deck having an operating time period which is determined by the length of the outgoing announcement. In such devices, announcements of any desired length (up to the capacity of the tape deck) may be recorded. When the announcement is subsequently played out to a caller, the answering device switches into a message recording mode shortly after completion of the announcement, whatever its length, without obliging a caller to wait an inordinate length of time before beginning his message. One means recognized in the art for doing this is monitoring of the announcement tape for the presence of speech signals as the tape is played out to a caller. After an absence of such signals for a short interval, perhaps 3 seconds, the announcement tape is deactivated and the answering device is switched into its message recording mode.
While telephone answering devices having a variable length announcement cycle are a considerable improvement over the earlier-described type, certain problems may be encountered in their use. One such problem may arise when a subscriber replaces a previously recorded announcement with one which is somewhat shorter. Under certain circumstances, the remaining portion of the old announcement may be reproduced to a caller following the end of the new announcement-- a clearly undesirable situation.